Record length. This field and the next field (total of four bytes) form the RDW (record descriptor word). See “Standard SMF Record Header” on page 13-1 for a detailed description.

2

2

SMF50SEG

2

binary

Segment descriptor (see record length field).

4

4

SMF50FLG

1

binary

System indicator Bit Meaning When Set 0 New record format 1 Subtypes used 2 Reserved. 3-6 Version indicators* 7 System is running in PR/SM mode.*See “Standard SMF Record Header” on page 13-1 for a detailed description.

5

5

SMF50RTY

1

binary

Record type 50 (X'32').

6

6

SMF50TME

4

binary

Time since midnight, in hundredths of a second, that the record was moved into the SMF buffer.

10

A

SMF50DTE

4

packed

Date when the record was moved into the SMF buffer, in the form 0cyydddF. See “Standard SMF Record Header” on page 13-1 for a detailed description.

14

E

SMF50SID

4

EBCDIC

System identification (from the SMFPRMxx SID parameter).

18

-

SMF50ID

8

EBCDIC

ID Name

SNA Controllers

The SMF 50 format depends upon the resource for which the tuning
I/O operation is collected. The following format is used for
the tuning statistics for input/output (I/O) operations for
SNA controllers

You can use VTAM tuning statistics to adjust operands in NCP
and VTAM definition statements to make your system run more
efficiently.

VTAM uses channel programs to send data to SNA controllers.
The amount of data that VTAM can read in one operation depends
on the number of buffers used by a read channel program and on
the size of each buffer.

Each tuning statistics record contains information about the
state of data-transfer operations between VTAM and one
channel-attached SNA controller (communication or
cluster controller). Each record contains statistics that cover
the time period since the last tuning statistics record was
written for that controller or channel-to-channel connection.

(Offset from beginning of record: 0)

18

-

SMF50SNA_NAME

8

EBCDIC

Controller name

26

-

SMF50SNA_DLRMAX

4

Binary

Dump load restart requests (DLRMAX)

30

-

SMF50SNA_CHWR

4

Binary

Write channel program count (CHWR)

34

-

SMF50SNA_CHRD

4

Binary

Read channel program count (CHRD)

38

-

SMF50SNA_ATTN

4

Binary

Total attention interrupts received (ATTN)

42

-

SMF50SNA_RDATN

4

Binary

Attentions on ends of READs (RDATN)

46

-

SMF50SNA_IPIU

4

Binary

Number of PDUs inbound (IPIU)

50

-

SMF50SNA_OPIU

4

Binary

Number of PDUs outbound (OPIU)

54

-

SMF50SNA_RDBUF

4

Binary

Total read buffers used (RDBUF)

58

-

SMF50SNA_SLODN

4

Binary

Number of slowdowns (SLODN)

62

-

SMF50SNA_EXLN

1

Binary

Extension length (including this field)

63

-

--

1

Binary

Reserved

64

-

SMF50SNA_VER

2

EBCDIC

Version = X'F0F4'

66

-

--

4

Binary

Reserved

70

-

--

4

Binary

Reserved

74

-

--

4

Binary

Reserved

78

-

--

4

Binary

Reserved

82

-

SMF50SNA_INLP

4

Binary

Number of inbound NLPs (INLP)

86

-

SMF50SNA_ONLP

4

Binary

Number of outbound NLPs (ONLP)

90

-

SMF50SNA_RDBUFNLP

4

Binary

Number of NLP read buffers

94

-

--

4

Binary

Reserved

98

-

--

4

Binary

Reserved

102

-

--

4

Binary

Reserved

106

-

--

4

Binary

Reserved

110

-

--

4

Binary

Reserved

Channel-to-Channel Connections

The SMF 50 format depends upon the resource for which the tuning
I/O operation is collected. The following format is used for
the tuning statistics for I/O operations for channel-to-channel
connections.

VTAM performs I/O operations across a channel-to-channel link.
By analyzing statistics provided by VTAM, you can select I/O
buffer sizes, data transfer delay, and other options that can
improve performance of these I/O operations.

VTAM uses channel programs to send data to other hosts. The
amount of data that VTAM can read in one operation depends on
the number of buffers used by a read channel program and on the
size of each buffer. Each tuning statistics record contains
information about the state of data-transfer operations between
two VTAMs (using channel-to-channel adapters).

Each record contains statistics that cover the time period
since the last tuning statistics record was written for that
controller or channel-to-channel connection

(Offset from beginning of record: 0)

18

-

SMF50CC_CTCA

8

EBCDIC

CTCA name (ID)

26

-

SMF50CC_DLRMAX

4

Binary

Dump load restart requests (DLRMAX)

30

-

SMF50CC_CHNRM

4

Binary

Normal-sized channel program count (CHNRM)

34

-

SMF50CC_CHMAX

4

Binary

Large-sized channel program count (CHMAX)

38

-

SMF50CC_ATTN

4

Binary

Total attention interrupts received (ATTN)

42

-

SMF50CC_WRBUF

4

Binary

Number of write buffers used (WRBUF). For packed channel programs the counts represent the number of bytes read or written. For old style (non-packed format) it is the number of buffers.

46

-

SMF50CC_IPIU

4

Binary

Number of PIUs inbound (IPIU)

50

-

SMF50CC_OPIU

4

Binary

Number of PIUs outbound (OPIU)

54

-

SMF50CC_RDBUF

4

Binary

Total input bytes used (RDBUF). For packed channel programs the counts represent the number of bytes read or written. For old style (non-packed format) it is the number of buffers.

58

-

SMF50CC_SLODN

4

Binary

Number of slowdowns (SLODN)

62

-

SMF50CC_EXLN

1

Binary

CTCA extension length (including this field)

63

-

SMF50CC_ATTYP

1

Binary

CTCA attachment type

64

-

SMF50CC_VER

2

EBCDIC

CTCA version = X'F0F1'

66

-

SMF50CC_TIMERS

4

Binary

Channel program starts due to timer trigger (TIMERS)

70

-

SMF50CC_QDPTH

4

Binary

Channel program starts due to queue depth limit trigger (QDPTH)

74

-

SMF50CC_BUFCAP

4

Binary

Channel program starts due to destination capacity limit trigger (BUFCAP)

78

-

SMF50CC_PRI

4

Binary

Channel program starts due to high priority request trigger (PRI)

82

-

--

32

Binary

Reserved

Multipath Channel (MPC) Connections Using XCF

The SMF 50 format depends upon the resource for which the tuning
I/O operation is collected. The following format is used for
for I/O operations for multipath channel (MPC) connections
using XCF.
(Multipath channel (MPC) connections use XCF or channel
connectivity.)

With XCF multipath channel attachment, VTAM uses the
MVS XCF signaling facility to send data to other hosts. By
analyzing statistics provided by VTAM, you can select I/O buffer
sizes and other options that can improve performance of these
I/O operations. The amount of data that VTAM can read in one
operation depends on the size of the read buffer.

Each tuning statistics record contains information about the
state of data-transfer operations between two VTAMs (using
multipath channel connections). Each record contains statistics
that cover the time period since the last tuning statistics
record was written for that multipath channel connection.

Notes: 1. Indicates fields used only in the first record for
statistics on the group.
2. Indicates fields used only in the subsequent record for
statistics on the read/write subchannel.
3. TSWEEP and QSWEEP are always 0 for HPDT MPC connections.

(Offset from beginning of record: 0)

18

-

SMF50MPCX_TRLE

8

EBCDIC

TRLE name

26

-

--

4

Binary

Reserved

30

-

SMF50MPCX_MVSTOK

8

Binary

MVS token

38

-

SMF50MPCX_TSWEEP

4

Binary

Number of timer sweeps (TSWEEP) 1, 3

38

-

SMF50MPCX_BYTECNTR

4

Binary

Number of received bytes 2

42

-

SMF50MPCX_QSWEEP

4

Binary

Number of queue sweeps (QSWEEP) 1, 3

42

-

SMF50MPCX_BYTECNTRO

4

Binary

Receive byte overflow count 2

46

-

SMF50MPCX_RECCNTWR

4

Binary

Number of write records 1

46

-

SMF50MPCX_XCF

4

EBCDIC

XCF identifier (XCF ) 2

50

-

SMF50MPCX_RECCNTRD

4

Binary

Number of read records 1

50

-

SMF50MPCX_BSIZE

4

Binary

Transmit block size (BSIZE) 2

54

-

SMF50MPCX_RECCNTRW

4

Binary

Number of READ/WRITE records 1

54

-

SMF50MPCX_RDWR

4

EBCDIC

READ/WRITE indicator (RDWR) 2

58

-

--

4

Binary

Reserved 1

58

-

SMF50MPXC_BYTECNTS

4

Binary

Sent byte count 2

62

-

SMF50MPXC_EXLN

1

Binary

CTCA extension length (including this field)

63

-

SMF50MPXC_ATTYP

1

Binary

CTCA attachment type X'01' 1 X'03' 2

64

-

SMF50MPXC_VER

2

EBCDIC

CTCA version = X'F0F2'

66

-

--

4

Binary

Reserved 1

66

-

SMF50MPXC_BYTECNTSO

4

Binary

Send byte overflow count 2

70

-

--

4

Binary

Reserved

74

-

--

4

Binary

Reserved

78

-

SMF50MPXC_MAXBYTES

4

Binary

Max transmit size (MAXBYTES) 2

82

-

--

4

Binary

Reserved

86

-

--

4

Binary

Reserved

90

-

--

4

Binary

Reserved

94

-

SMF50MPXC_INLP

4

Binary

Number of inbound NLPs (INLP)

98

-

SMF50MPXC_ONLP

4

Binary

Number of outbound NLPs (ONLP)

102

-

SMF50MPXC_BYTECNTNLP

4

Binary

NLP byte count

106

-

SMF50MPXC_BYTECNT0NLP

4

Binary

NLP byte count overflow

Multipath Channel (MPC) Connections Using Channels

The SMF 50 format depends upon the resource for which the tuning
I/O operation is collected. The following format is used for I/O
operations for multipath channel connections using channels.
(Multipath channel (MPC) connections use XCF or channel
connectivity.)

With MPC channel connectivity attachment, VTAM performs
I/O operations across multiple single-direction channel
links. By analyzing statistics provided by VTAM, you can
select I/O buffer sizes, data transfer delay, and other
options that can improve performance of these I/O operations.

VTAM uses channel programs or Direct Memory Access (DMA)
to transmit and receive data. The amount of data that VTAM
can read in one operation depends on the size of the read
buffer. Each tuning statistics record contains information
about the state of data-transfer operations across the multipath
channel connection.

Each record contains statistics that cover the time period
since the last tuning statistics record was written for that
multipath channel connection.

Note: Non-HPDT multipath channel uses a special data
block called a sweep that is exchanged with the adjacent host
to verify that data has not been lost. A host initiating a sweep
request holds all outbound multipath channel transmissions until
it receives a sweep reply from the adjacent host.

A sweep is initiated when either of the following occurs:

A timer expires in the host with the higher subarea number.

Receive queue depth in either host is excessive.

The host initiating the sweep sends the sequence number of the
last output transmit block. The adjacent host compares this
number with its last input transmit block sequence number. The
adjacent host then sends a response to the initiating host that
includes the adjacent host last output transmit block sequence
number. The initiating host makes the same comparison. If the
numbers do not match, or the sweep does not complete within a time
limit, the multipath channel group will be inactivated. Otherwise,
normal flow continues. The tuning statistics contain a count of
how many sweeps are initiated by an expired timer and how many are
initiated by excessive receive queue depth.

Note: For HPDT MPC connections, tsweep and qsweep are
always 0.

Notes: 1. Indicates fields used only in the first record for
statistics on the group.
2. Indicates fields used only in subsequent records for
statistics on each write and each read subchannel.
3. TSWEEP and QSWEEP are always 0 for HPDT MPC connections.
4. Indicates fields used only in subsequent records for
statistics on each OSA-Express or Hipersockets datapath queue